Final answer:
A follicular cast is caused by a clog in the hair follicles, which can lead to the development of lesions. In acne, the clog is usually a result of complex lipids, fatty acids, and dead skin cells, creating a favorable environment for bacteria.
Step-by-step explanation:
A follicular cast is caused by a clog in the hair follicles, which can lead to the development of lesions. In the case of acne, the clog is usually a result of complex lipids, fatty acids, and dead skin cells. This clog creates a favorable environment for bacteria, such as Propionibacterium acnes, which can then damage the hair follicle and cause inflammatory lesions.